Remove Java to Python stdout and stderr forwarding

We noticed that running macros and scripts (e.g. ij.py.run_script())
produces a duplicate stdout and stderr. We traced the duplicating
output to the OutputListener forwarding removed in this commit. But
why were we forwarding the stdout and stderr in the first place? Looking
at commit db9bae3 we can see that we carried the OutputListener
forwarding from pyjnius to JPype. JPype already handles stdout and
stderr forwarding, thus a duplicate is generated. Apparently we
never noticed this. This commit removes the duplicate forwarding.

src/imagej/__init__.py

@@ -46,7 +46,7 @@
 import numpy as np
 import scyjava as sj
 import xarray as xr
-from jpype import JImplementationFor, JImplements, JOverride, setupGuiEnvironment
+from jpype import JImplementationFor, setupGuiEnvironment
 from scyjava.config import find_jars
 
 import imagej.convert as convert
@@ -1278,23 +1278,6 @@ def _create_gateway():
 
     ij = ImageJ()
 
-    # Forward stdout and stderr from Java to Python.
-    @JImplements("org.scijava.console.OutputListener")
-    class JavaOutputListener:
-        @JOverride
-        def outputOccurred(self, e):
-            source = e.getSource().toString
-            output = e.getOutput()
-            if source == "STDOUT":
-                sys.stdout.write(output)
-            elif source == "STDERR":
-                sys.stderr.write(output)
-            else:
-                sys.stderr.write(f"[{source}] {output}")
-
-    ij.py._outputMapper = JavaOutputListener()
-    ij.console().addOutputListener(ij.py._outputMapper)
-
     # Register a Python-side script runner object, used by the
     # org.scijava:scripting-python script language plugin.
     if callable(getattr(sj, "enable_python_scripting", None)):